If your vehicle is equipped with a factory spoiler, it will have to be removed before installing this item. :: BENZ VS BMW : Color Matte Black. Material ABS Plastic(Acrylonitrile Butadiene Styrene).
The design of the wing, which wasn't adequately curved when designed for the rear window glass shape, separates from the glass at one end on sunny days and then settles down into place on cooler days. The adhesive tape is not strong enough to keep it firmly onto the rear glass. And when the wing expands from the heat, it raises off the glass.